shrinkage stoping[′shriŋ·kij ‚stōp·iŋ]
periodic filling of a worked-out space with ore broken out from the main body during underground mining of a deposit. The filling takes place as a result of blasting of ore from the rock mass. The accumulated ore serves as a platform for the miners working in the stope (stoping block) and, to a certain extent, prevents exfoliation of the enclosing rock. The enclosing rock is supported by means of interchamber and interfloor pillars of ore, unexcavated ore-free sections, and the broken mass, if it is raised after working out the reserves of the block. To reduce losses when using shrinkage stoping systems for the extraction of a valuable mineral from thin beds, the cutting is done without drift and entry pillars, replacing them with stulls and other types of support. Upon completion of stoping in the block, the accumulated ore is emptied completely.
In addition to the conventional shrinkage stoping system, when the broken ore (mineral) fills the worked-out space to the full height of the block (or level), there is also a version of the system with partial shrinkage stoping, in which the broken ore fills the worked-out space for only part of the height of the block (bed or sublevel).
The shrinkage stoping method is most suitable for lode deposits 0.5 to 4-5 m thick with persistent bedding and an angle of not less than 60°, which are represented by hard, stableores and stable enclosing rock. In the case of very thick beds, the shrinkage stoping system can be used only at an extremely steep dip angle (85°-90°).
REFERENCEAgoshkov, M. I., S. S. Borisov, and V. A. Boiarskii. Razrabotka rudnykh i nerudnykh mestorozhdenii, 2nd ed. Moscow, 1970.
A. S. VORONIUK